Multiscale Approaches to Formation of Thermoplastic Prepreg Short Carbon Fiber

The fabrication of prepreg carbon fiber typically involves continuous fibers or fabrics which cannot be easily translated to discontinuous fibers. Additionally, applying prepreg coatings typically involves resins of relatively high viscosity making facilitating traditional coating methods which are not receptive to short fibers. In this work we demonstrate the application of high performance thermoplastic polyimides to short carbon fibers. We show the development of a variety of coating techniques used to produce prepregs from the solution and melt states. The quality, thickness, and uniformity of these coatings are assessed using fluorescence and scanning electron microscopy. We illustrate the capabilities of these methods to apply coatings subject to interfacial conditions. Furthermore we show the effect of interfacial treatments (oxidation, reduction, sizing, etc.) on coating quality. Through large scale techniques, it is possible to fabricate short fiber prepregs for use in high performance composite materials.